/*
 * Copyright 1999-2004 The Apache Software Foundation
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */


package relocated.morphia.org.apache.commons.collections;


import java.util.Map;


/**
 * A default implementation of {@link Map.Entry}
 *
 * @author <a href="mailto:jstrachan@apache.org">James Strachan</a>
 * @author <a href="mailto:mas@apache.org">Michael A. Smith</a>
 * @since 1.0
 */

public class DefaultMapEntry implements Map.Entry {

  private Object key;
  private Object value;

  /**
   * Constructs a new <Code>DefaultMapEntry</Code> with a null key and null value.
   */
  public DefaultMapEntry() {
  }

  /**
   * Constructs a new <Code>DefaultMapEntry</Code> with the given key and given value.
   *
   * @param key the key for the entry, may be null
   * @param value the value for the entry, may be null
   */
  public DefaultMapEntry(final Object key, final Object value) {
    this.key = key;
    this.value = value;
  }

  /**
   * Implemented per API documentation of {@link Map.Entry#equals(Object)}
   */
  public boolean equals(final Object o) {
    if (o == null) {
      return false;
    }
    if (o == this) {
      return true;
    }

    if (!(o instanceof Map.Entry)) {
      return false;
    }
    final Map.Entry e2 = (Map.Entry) o;
    return ((getKey() == null ? e2.getKey() == null : getKey().equals(e2.getKey())) && (getValue() == null
      ? e2.getValue() == null
      : getValue().equals(e2.getValue())));
  }


  /**
   * Implemented per API documentation of {@link Map.Entry#hashCode()}
   */
  public int hashCode() {
    return ((getKey() == null ? 0 : getKey().hashCode()) ^ (getValue() == null ? 0 : getValue().hashCode()));
  }


  // Map.Entry interface
  //-------------------------------------------------------------------------

  /**
   * Returns the key.
   *
   * @return the key
   */
  public Object getKey() {
    return key;
  }


  /**
   * Returns the value.
   *
   * @return the value
   */
  public Object getValue() {
    return value;
  }

  // Properties
  //-------------------------------------------------------------------------

  /**
   * Sets the key.  This method does not modify any map.
   *
   * @param key the new key
   */
  public void setKey(final Object key) {
    this.key = key;
  }

  /**
   * Note that this method only sets the local reference inside this object and does not modify the original Map.
   *
   * @param value the new value
   * @return the old value of the value
   */
  public Object setValue(final Object value) {
    final Object answer = this.value;
    this.value = value;
    return answer;
  }

}
